Development and Validation of an Engineering Simulation Model in FLIGHTLAB with Customized Modeling Enhancements

A high fidelity engineering simulation model has been developed in FLIGHTLAB for a Sikorsky production helicopter to support future design modifications. The simulation model consists of major subsystems for main rotor, tail rotor, fuselage, empennage, landing gear, flight control system, and propulsion system. As the manufacturer of the aircraft, Sikorsky is able to provide a complete and validated set of model data required for a high quality engineering model. A large database of flight test records was used to conduct a comprehensive validation effort to ensure the model quality and fidelity. The trim tests include hover (both in and out-of-ground effect), lateral and longitudinal low-speed flight, level flight, vertical climb, forward climb and descent, and autorotation. The dynamic response tests include longitudinal, lateral, collective, and pedal step and doublet control responses in both hover and cruise. The model predictions satisfactorily correlate with the test data in most of the test cases covering a broad range of configurations and flight conditions. For the most challenging low-speed flight regime, a set of customized modeling enhancements were implemented via the "user-defined subsystems" in FLIGHTLAB. These enhancements allow for more sophisticated adjustment of some semi-empirical corrections to address certain model limitations in the main rotor ground effect, the main rotor inflow and interference, and the tail rotor inflow and interference. The model-data correlation in low-speed flight was significantly improved by implementing these model enhancements, resulting in a high fidelity engineering simulation model.